It is disclosed in Japanese Patent Publication No. 240075/1988 that cyclic urea compounds represented by the following formula (P) are contained in thermosetting resin composition. ##STR3##
A heterocyclic ring of these cyclic urea compounds is limited by a seven-member ring or more (that is n is 2 or more). A five-member ring and a six-member ring are not disclosed.
Compounds containing a five- to seven-member ring which have no oxygen connected directly to a carbonyl group of cyclic urea derivatives represented by the above described formula (P) are disclosed in J. Org. Chem., Vol, 43, No. 8. 1978 by Henri Ulrich et al. This report is characterized by that the compounds containing a five-member ring and a six-member ring do not cause a ring-opening by a thermal decomposition which is one of specific features of a cyclic urea structure. The following compound represented by the following formula (Q) is also disclosed in J. Org. Chem. 29 (11), 3347-50(1964) by James N. Tilley et al. ##STR4##
This compound is obtained by a complicated method.